Reduced-pressure, multi-orientation, liquid-collection canister

ABSTRACT

An apparatus for use in a multi-orientation liquid collection canister to collect liquid from a tissue site is provided. The apparatus includes a substantially planar, liquid-air separator disposed on at least one wall of the multi-orientation liquid collection canister to prevent the liquid from exiting the multi-orientation liquid collection canister. The apparatus further includes an elongated member connected to the liquid-air separator and extending away from the liquid-air separator into a first space of the multi-orientation liquid collection canister. The elongated member has a membrane defining a second space along at least a portion of a length of the elongated member. At least a portion of the membrane allows gaseous communication between the first space and the second space.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/211,172, filed Aug. 16, 2011, which claims the benefit of U.S.Provisional Application No. 61/374,995, filed Aug. 18, 2010, which ishereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to reduced pressure treatmentsystems and more particularly to a reduced-pressure, liquid-collectioncanister having a filter that allows operation of the canister inmultiple orientations.

2. Description of Related Art

Clinical studies and practice have shown that providing a reducedpressure in proximity to a tissue site augments and accelerates thegrowth of new tissue at the tissue site. The applications of thisphenomenon are numerous, but one particular application of reducedpressure involves treating wounds. This treatment (frequently referredto in the medical community as “negative pressure wound therapy,”“reduced pressure therapy,” or “vacuum therapy”) provides a number ofbenefits, including migration of epithelial and subcutaneous tissuescells, improved blood flow, and micro-deformation of tissue at the woundsite. Together these benefits result in increased development ofgranulation tissue and faster healing times. Typically, reduced pressureis applied by a reduced pressure source to tissue through a porous pador other manifold device. In many instances, wound exudate and otherliquids from the tissue site are collected within a canister to preventthe liquids from reaching the reduced pressure source.

SUMMARY

The problems presented by existing reduced pressure systems and liquidcollection canisters are solved by the systems and methods of theillustrative embodiments described herein. A reduced pressure treatmentsystem for applying reduced pressure treatment to a tissue site includesa reduced pressure source, a liquid-collection canister, and a manifoldpositioned at the tissue site and in fluid communication with theliquid-collection canister. In one embodiment, the liquid-collectioncanister includes at least one canister wall defining a first spaceconfigured to collect liquid from the tissue site. A canister outlet isconfigured to allow communication between the reduced pressure sourceand the first space. A substantially planar, liquid-air separator isdisposed adjacent the canister outlet to prevent the liquid from exitingthe first space through the canister outlet. An elongated member isconnected to the liquid-air separator and extends away from theliquid-air separator into the first space. The elongated member has amembrane defining a second space along at least a portion of a length ofthe elongated member, and at least a portion of the membrane allowsgaseous communication between the first space and the second space.

In another embodiment, an apparatus for use in a multi-orientationliquid collection canister to collect liquid from a tissue site isprovided. The apparatus includes an elongated member configured forfluid connection to an outlet of the liquid collection canister. Theelongated member having a membrane defining a space along at least aportion of a length of the elongated member, and at least a portion ofthe membrane allows gaseous communication, but substantially preventsliquid communication through the at least a portion of the membrane.

In yet another embodiment, a reduced pressure treatment system forapplying reduced pressure treatment to a tissue site is provided. Thesystem includes a reduced pressure source, a liquid-collection canister,and a manifold positioned at the tissue site and in fluid communicationwith the liquid-collection canister. The liquid-collection canisterincludes a chamber configured to collect liquid from the tissue site. Acanister outlet is in fluid communication with the reduced pressuresource. The liquid-collection canister further includes a flexiblemember having a gas communication pathway at least partially defined bya flexible membrane. The flexible member is positioned in the chambersuch that the gas communication pathway is in fluid communication withthe canister outlet and at least a portion of the flexible membrane isgas permeable and substantially liquid impermeable.

Still, in another embodiment, a liquid-collection canister forcollecting liquid from a tissue site is provided. The liquid-collectioncanister includes a chamber configured to collect liquid from the tissuesite. A canister outlet is in fluid communication with the reducedpressure source. The liquid-collection canister further includes aflexible member having a gas communication pathway at least partiallydefined by a flexible membrane. The flexible member is positioned in thechamber such that the gas communication pathway is in fluidcommunication with the canister outlet and at least a portion of theflexible membrane is gas permeable and substantially liquid impermeable.

In another embodiment, an apparatus is provided for use in amulti-orientation liquid collection canister to collect liquid from atissue site to which reduced pressure treatment is applied. Theapparatus includes a flexible member configured for fluid connection toan outlet of the liquid-collection canister. The flexible member havinga gas communication pathway at least partially defined by a flexiblemembrane. The gas communication pathway is adapted to be positioned influid communication with the canister outlet and at least a portion ofthe flexible membrane is gas-permeable and substantially liquidimpermeable.

In yet another embodiment, a reduced pressure treatment system forapplying reduced pressure treatment to a tissue site is provided. Thesystem includes a reduced pressure source, a liquid-collection canister,and a manifold positioned at the tissue site and in fluid communicationwith the liquid-collection canister. The liquid-collection canisterincludes at least one canister wall defining a chamber configured tocollect liquid from the tissue site. A canister outlet is in fluidcommunication with the reduced pressure source. A conduit is positionedin the chamber. The conduit has a conduit wall forming a gascommunication lumen. The gas-communication lumen is fluidly connected tothe canister outlet. A liquid-air separator is operably associated withthe conduit to allow gas communication, but substantially preventsliquid communication between the chamber and the gas-communicationlumen.

In still another embodiment, an apparatus is provided for use in amulti-orientation liquid collection canister to collect liquid from atissue site to which reduced pressure treatment is applied. Theapparatus includes a conduit adapted to fluidly connect to an outlet ofthe liquid-collection canister. The conduit having a gas-communicationlumen at least partially defined by a conduit wall. A liquid-airseparator is operably associated with the conduit to allowgas-communication, but substantially prevents liquid communicationbetween the gas-communication lumen and an area surrounding the conduit.

In still another embodiment, a method is provided for retrofitting awound fluid collection canister to allow collection of wound fluid inmultiple orientations of the wound fluid collection canister. The methodincludes fluidly connecting an elongated member to an outlet of thewound fluid collection canister. At least a portion of the elongatedmember extends into a liquid collection area of the wound fluidcollection canister. The method further includes allowing gas exchangebetween an inner space of the elongated member and the liquid collectionarea; and substantially preventing liquid exchange between the innerspace and the liquid collection area.

Other objects, features, and advantages of the illustrative embodimentswill become apparent with reference to the drawings and detaileddescription that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of a reduced pressure treatmentsystem having a reduced pressure treatment unit and a multi-orientation,liquid-collection canister according to an illustrative embodiment;

FIG. 2 illustrates an exploded perspective view of the liquid-collectioncanister of FIG. 1 and filter elements associated with theliquid-collection canister according to an illustrative embodiment;

FIG. 3 illustrates a perspective view of the filter element connected toa base of the liquid-collection canister of FIG. 2;

FIG. 4A illustrates a cross-sectional view of the filter element of FIG.3 taken at 4-4;

FIG. 4B illustrates a cross-sectional view of a filter element accordingto an illustrative embodiment, the cross-section view similar to that ofFIG. 4A;

FIGS. 5A-5D illustrates different configurations of a filter elementpositioned in the liquid-collection canister of FIG. 2 according to anillustrative embodiment;

FIGS. 6A-6C illustrates different orientations of a liquid-collectioncanister having the filter configuration illustrated in FIG. 5B;

FIG. 7 illustrates a liquid-collection canister having a barb connectorfor connecting a filter element according to an illustrative embodiment;

FIG. 8 illustrates a cross-sectional side view of the filter element andbarb connector of FIG. 7 according to an illustrative embodiment; and

FIG. 9 illustrates an exploded perspective view of a liquid-collectioncanister according to an illustrative embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following detailed description of several illustrativeembodiments, reference is made to the accompanying drawings that form apart hereof, and in which is shown by way of illustration specificpreferred embodiments in which the invention may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention, and it is understood that otherembodiments may be utilized and that logical structural, mechanical,electrical, and chemical changes may be made without departing from thespirit or scope of the invention. To avoid detail not necessary toenable those skilled in the art to practice the embodiments describedherein, the description may omit certain information known to thoseskilled in the art. The following detailed description is, therefore,not to be taken in a limiting sense, and the scope of the illustrativeembodiments are defined only by the appended claims.

The term “reduced pressure” as used herein generally refers to apressure less than the ambient pressure at a tissue site that is beingsubjected to treatment. In most cases, this reduced pressure will beless than the atmospheric pressure at which the patient is located.Alternatively, the reduced pressure may be less than a hydrostaticpressure associated with tissue at the tissue site. Although the terms“vacuum” and “negative pressure” may be used to describe the pressureapplied to the tissue site, the actual pressure reduction applied to thetissue site may be significantly less than the pressure reductionnormally associated with a complete vacuum. Reduced pressure mayinitially generate fluid flow in the area of the tissue site. As thehydrostatic pressure around the tissue site approaches the desiredreduced pressure, the flow may subside, and the reduced pressure is thenmaintained. Unless otherwise indicated, values of pressure stated hereinare gauge pressures. Similarly, references to increases in reducedpressure typically refer to a decrease in absolute pressure, whiledecreases in reduced pressure typically refer to an increase in absolutepressure.

The term “tissue site” as used herein refers to a wound or defectlocated on or within any tissue, including but not limited to, bonetissue, adipose tissue, muscle tissue, neural tissue, dermal tissue,vascular tissue, connective tissue, cartilage, tendons, or ligaments.The term “tissue site” may further refer to areas of any tissue that arenot necessarily wounded or defective, but are instead areas in which itis desired to add or promote the growth of additional tissue. Forexample, reduced pressure tissue treatment may be used in certain tissueareas to grow additional tissue that may be harvested and transplantedto another tissue location.

Referring to FIG. 1, a reduced pressure treatment system 100 forapplying a reduced pressure to a tissue site 101 of a patient accordingto an illustrative embodiment includes a canister 102 in fluidcommunication with a reduced pressure source 108 and a reduced pressuredressing 112 that is positioned at the tissue site 101. The reducedpressure dressing 112 is fluidly connected to an inlet 103 of thecanister 102 by a conduit 120. The conduit 120 may fluidly communicatewith the reduced pressure dressing 112 through a tubing adapter 124.

In at least one embodiment described herein, the canister 102 used tocollect exudate or other fluids from the tissue site 101 is configuredto allow the canister 102 to operate in multiple orientations even asthe canister 102 begins to fill with liquid. The canister 102 preferablyincludes a protected gas communication pathway, or dry space, thatallows continued gas communication with a liquid collection chamber 104of the canister 102 as exudate and other liquids collect within theliquid collection chamber 104. The path of fluid communication in thereduced pressure treatment system 100 is as follows. Reduced pressure issupplied to the gas communication pathway of the canister 102 by thereduced pressure source 108. Typically this occurs by the reducedpressure source 108 drawing gaseous fluids, such as air, from the gascommunication pathway. As the pressure within the gas communicationpathway falls, gas flows from the liquid collection chamber 104 of thecanister 102 to the gas communication pathway, thus resulting in a dropin pressure within the liquid collection chamber 104. Liquid isprevented from flowing into the gas communication pathway by ahydrophobic element, an oleophobic element, or some other type ofliquid-blocking membrane, liquid-air separator, or other device. Thereduced pressure within the liquid collection chamber 104 is transmittedto the dressing 112 at the tissue site 101, which allows fluids (bothgases and liquids) to flow from the tissue site 101 to the liquidcollection chamber 104. The liquid collects within the liquid collectionchamber 104. In some embodiments, multiple fluid communication portsbetween the liquid collection chamber 104 and the gas communicationpathway allow continued gaseous communication between the liquidcollection chamber 104 and the gas communication pathway even as theliquid collection chamber 104 fills with liquids and blocks some ofthese communication ports. This configuration permits continued supplyof reduced pressure to the liquid collection chamber 104 until theliquid collection canister is almost completely full of liquid. As analternative to the multiple ports, a large common port may be providedso that only a portion of the port is covered or blocked by liquid asthe canister 102 fills.

In the embodiment illustrated in FIG. 1, the reduced pressure source 108is an electrically-driven vacuum pump. In another implementation, thereduced pressure source 108 may instead be a manually-actuated ormanually-charged pump that does not require electrical power. Thereduced pressure source 108 instead may be any other type of reducedpressure pump, or alternatively a wall suction port such as thoseavailable in hospitals and other medical facilities. The reducedpressure source 108 may be housed within or used in conjunction with areduced pressure treatment unit 140, which may also contain sensors,processing units, alarm indicators, memory, databases, software, displayunits, and user interfaces 110 that further facilitate the applicationof reduced pressure treatment to the tissue site 101. In one example, asensor or switch (not shown) may be disposed at or near the reducedpressure source 108 to determine a source pressure generated by thereduced pressure source 108. The sensor may communicate with aprocessing unit that monitors and controls the reduced pressure that isdelivered by the reduced pressure source 108.

The reduced pressure dressing 112 includes a distribution manifold 144adapted to be positioned at the tissue site 101, and a cover 148, ordrape, that is positioned over the distribution manifold 144 to maintainreduced pressure beneath the cover 148 at the tissue site 101. The cover148 may extend beyond a perimeter of the tissue site 101 and may includean adhesive or bonding agent on the cover 148 to secure the cover 148 totissue adjacent the tissue site 101. In one embodiment, the adhesivedisposed on cover 148 may be used to seal between the tissue and thecover 148 to prevent leakage of reduced pressure from the tissue site101. In another embodiment, a seal layer (not shown) such as, forexample, a hydrogel or other material may be disposed between the cover148 and the tissue to augment or substitute for the sealing propertiesof the adhesive.

The distribution manifold 144 of the reduced pressure dressing 112 isadapted to contact the tissue site 101. The distribution manifold 144may be partially or fully in contact with the tissue site 101 beingtreated by the reduced pressure dressing 112. When the tissue site 101is a wound, the distribution manifold 144 may partially or fully fillthe wound.

The distribution manifold 144 may be any size, shape, or thicknessdepending on a variety of factors, such as the type of treatment beingimplemented or the nature and size of the tissue site 101. For example,the size and shape of the distribution manifold 144 may be customized bya user to cover a particular portion of the tissue site 101, or to fillor partially fill the tissue site 101. The distribution manifold 144 mayhave, for example, a square shape, or may be shaped as a circle, oval,polygon, an irregular shape, or any other shape.

In one illustrative embodiment, the distribution manifold 144 is a foammaterial that distributes reduced pressure to the tissue site 101 whenthe distribution manifold 144 is in contact with or near the tissue site101. The foam material may be either hydrophobic or hydrophilic. In onenon-limiting example, the distribution manifold 144 is an open-cell,reticulated polyurethane foam such as GranuFoam® dressing available fromKinetic Concepts, Inc. of San Antonio, Tex.

In the example in which the distribution manifold 144 is made from ahydrophilic material, the distribution manifold 144 also functions towick fluid away from the tissue site 101, while continuing to providereduced pressure to the tissue site 101 as a manifold. The wickingproperties of the distribution manifold 144 draw fluid away from thetissue site 101 by capillary flow or other wicking mechanisms. Anexample of a hydrophilic foam is a polyvinyl alcohol, open-cell foamsuch as V.A.C. WhiteFoam® dressing available from Kinetic Concepts, Inc.of San Antonio, Tex. Other hydrophilic foams may include those made frompolyether. Other foams that may exhibit hydrophilic characteristicsinclude hydrophobic foams that have been treated (including plasmatreatment) or coated to provide hydrophilicity. In still anotherembodiment, the distribution manifold 144 may be a non-woven materialsuch as Libeltex™ TDL2, manufactured by Libeltex Group.

The distribution manifold 144 may further promote granulation at thetissue site 101 when a reduced pressure is applied through the reducedpressure dressing 112. For example, any or all of the surfaces of thedistribution manifold 144 may have an uneven, coarse, or jagged profilethat causes microstrains and stresses at the tissue site 101 whenreduced pressure is applied through the distribution manifold 144. Thesemicrostrains and stresses have been shown to increase new tissue growth.

In one embodiment, the distribution manifold 144 may be constructed frombioresorbable materials that do not have to be removed from a patient'sbody following use of the reduced pressure dressing 112. Suitablebioresorbable materials may include, without limitation, a polymericblend of polylactic acid (PLA) and polyglycolic acid (PGA). Thepolymeric blend may also include without limitation polycarbonates,polyfumarates, and capralactones. The distribution manifold 144 mayfurther serve as a scaffold for new cell-growth, or a scaffold materialmay be used in conjunction with the distribution manifold 144 to promotecell-growth. A scaffold is a substance or structure used to enhance orpromote the growth of cells or formation of tissue, such as athree-dimensional porous structure that provides a template for cellgrowth. Illustrative examples of scaffold materials include calciumphosphate, collagen, PLA/PGA, coral hydroxy apatites, carbonates, orprocessed allograft materials.

Referring now to FIGS. 1 and 2, the canister 102 includes a canisterhousing 143 having a basin portion 145 and a lid portion 146. The lidportion 146 may be formed by an exit wall 142 that is substantiallyplanar and is capable of mating with the basin portion 145 to form theliquid collection chamber 104. While the basin portion 145 is formedfrom a basin wall 150 that includes curved contours to create a crescentshape, the basin portion 145 and lid portion 146 may instead form acanister that is cylindrical, cubical, spherical, rectangular cubical,or any other shape. It should also be noted that the canister 102 maynot include separate basin and lid portions, but rather may be formedfrom a substantially unitary housing. In such an embodiment, theliquid-collection chamber 104 may be defined by a single wall.Alternatively, the liquid-collection chamber 104 may be formed by aplurality of walls.

The canister 102 includes the inlet 103 that is fluidly connected to theconduit 120, a canister outlet 156 that is fluidly connected to thereduced pressure source 108, and a substantially planar liquid-airseparator 160 that is operatively associated with the outlet 156 toprevent liquid from exiting the canister 102 through the canister outlet156. The inlet 103 may be positioned on a wall 178 disposed in arecessed region of the basin portion 145. In one embodiment, the outlet156 is positioned in the exit wall 142, and the substantially planarliquid-air separator 160 is positioned adjacent to the outlet 156 andsecured to the exit wall 142. In some embodiments, the exit wall 142 mayinclude a recessed region 158 that aids in providing a secure connectionfor the liquid-air separator 160. The outlet 156 allows fluidcommunication between the canister 102 and the reduced pressure source108 such that a reduced pressure is capable of being maintained withinthe canister 102. This reduced pressure is capable of being transmittedto the tissue site through the inlet 103, the conduit 120, the tubingadapter 124, and the distribution manifold 144. The reduced pressuredraws exudate and other fluids from the tissue site 101 into thecanister 102. The substantially planar liquid-air separator 160 preventsliquids that that are drawn into the canister 102 from exiting thecanister 102 through the outlet 156 and contaminating the reducedpressure source 108.

In an illustrative embodiment, the substantially planar liquid-airseparator 160 may be a hydrophobic or oleophobic filter that preventspassage of liquids through the outlet 156. An example of a suitablehydrophobic material includes an expanded PTFE laminate such as ahydrophobic medical membrane manufactured by WL Gore & Associates,Newark, Del.; the Aspire® ePTFE filter membrane manufactured by GeneralElectric; or any other suitable membrane. In one embodiment, such alaminate may have a 1.0 micron reference pore size on non wovenpolyester with a thickness range of 0.17 mm-0.34 mm. The hydrophobicmedical membrane may have a minimum air flow of 18 LPM/cm² @ 1 bar (15PSI) and a minimum water entry pressure of 1.1 bar (16.0 PSI). Anexample of a suitable oleophobic material includes an oleophobicexpanded PTFE membrane having a 1.0 micron reference pore size on nonwoven polyester with a thickness range of 0.15 mm-0.39 mm. Theoleophobic membrane may have a minimum air flow of 12 LPM/cm² @ 1 bar(15 PSI) and a minimum water entry pressure of 0.8 bar (12.0 PSI).Alternatively, the substantially planar liquid-air separator 160 may bea gravity-based barrier system, or a device that includes a hydrophilicsurface to encourage condensation or other separation of liquid from afluid stream when the fluid stream passes over the surface. Otherexamples of liquid-air separators 160 may include sintered metals,sintered nylons, specialty fiber filters such as those manufactured byFiltrona, plastics that have been plasma treated to cause the surface tobe hydrophilic, or any other material or device that is capable ofseparating liquid from a fluid stream, or that is otherwise capable ofsubstantially preventing the passage of liquid while allowing thepassage of gases.

In accordance with one embodiment, the canister 102 includes anelongated member 162 that forms a conduit that allows gaseouscommunication between the liquid collection chamber 104 and the canisteroutlet 156 for maintaining reduced pressure in the liquid collectionchamber 104 while substantially preventing liquid communication. Theterm “elongated” as used herein generally refers to a portion havingnotably a longer length than width. The elongated member 162 may have amembrane or a wall that defines the gaseous communication space. Theelongated member 162 and thus the membrane or wall of the elongatedmember may be rigid, semi-rigid, rigid-in-sections, and/or flexible. Forexample, in some embodiments, the elongated member 162 may be pre-shapedsuch as with a foil or heat-formed plastic sheet to fit the canister 102or any other canister design. In other embodiments, elongated member 162may extend naturally based on an orientation of the canister 102. Theterm “flexible” as used herein generally means capable of being bent orshaped. In some embodiments, the shaping of the elongated member may notinvolve plastic deformation of any components of the elongated member,but in other embodiments, one or more elements of the elongated membermay be plastically deformed such that the elongated member retains itsshape after being manipulated and positioned within the canister. Insome embodiments, the term “flexible” may refer to the ability of theelongated member to conform or be conformed to different shapes orarrangements within the canister without the use of special tools orequipment, such as for example by hand placement. In some embodiments,the elongated member 162 may include one or more portions/segmentsspaced along the membrane that allow the gaseous communication betweenthe liquid collection chamber 104 and the canister outlet 156. In otherembodiments, the membrane may substantially comprise a material thatallows gaseous communication, but substantially prevents liquidcommunication.

In one embodiment, the elongated member 162 is connected to thesubstantially planar liquid-air separator 160 such that fluidcommunication is provided between the outlet 156 and the interior spaceof the elongated member 162. For example, the elongated member 162 maybe welded to the liquid-air separator 160. In other embodiments, theelongated member 162 may be connected to the substantially planarliquid-air separator 160 using an adhesive material or by any othersuitable means. Alternatively, in some embodiments, the substantiallyplanar liquid-air separator 160 and the elongated member 162 are notseparate components, but rather may be manufactured as a substantiallyunitary liquid-air separator. When coupled, the substantially planarliquid-air separator 160 and the elongated member 162 serve the sameliquid-air-separation purpose of allowing air to move from the canister102.

In certain embodiments, the canister 102 may also include an absorbentmaterial for absorbing exudate and other fluids drawn from the tissuesite 101. Additionally, the canister 102 may include a solidificationsubstance such as isolyzer. Isolyzer reacts with a serum, plasma, tissueand organ homogenates, blood, or other water containing infectiousliquids to form a solid substance.

FIG. 3 illustrates an embodiment depicting the liquid-air separator 160and the elongated member 162 connected to one another and to the lidportion 146 of the canister 102. The liquid-air separator 160 issubstantially planar to the lid portion 146. It should be noted that theshape and size of the liquid-air separator 160 may change depending onthe shape and size of the lid portion 146, the outlet 156, or therecessed region 158 of the lid portion 146.

In one embodiment, the elongated member 162 is substantiallyperpendicular to the substantially planar liquid-air separator 160.However, in other embodiments, the elongated member 162 may be parallelto the substantially planar liquid-air separator 160 or connected at anyangle at the point of attachment. The elongated member 162 extends awayfrom the substantially planar liquid-air separator 160 and into theliquid collection chamber 104 of the canister 102. The elongated member162 may be of varying length and width depending upon the size andconfiguration the canister 102. The elongated member 162 may becomprised of the same material as the liquid-air separator 160, asdescribed above, or may be made of any other material that is capable ofsubstantially preventing the passage of liquid while allowing thepassage of gas. However, the elongated member 162 does not allow gaseouscommunication through portions of the elongated member 162 which arecurrently covered with liquid. Therefore, in the disclosed embodiments,the elongated member 162 is advantageously positioned, shaped, and/ormanufactured to cover multiple planes within the liquid collectionchamber 104 so as to enable the canister 102 to continue to receivereduced pressure from the reduced pressure source 108 in multiple, ifnot all, orientations of the canister 102. In addition to operating inmultiple orientations, the elongated member 162 also enables continuedair flow when there is fluid slosh that temporarily blocks exposedportions of the elongated member 162.

Additionally, in some embodiments, the elongated member 162 may comprisesubstantially of a liquid-air separator material. In another embodiment,the elongated member 162 may have one side that is liquid and gasimpermeable, while the other side may comprise substantially of aliquid-air separator material. In yet another embodiment, the elongatedmember 162 may contain optimally placed portions that are liquid-airseparators while the remaining portion of the elongated member 162 isliquid and gas impermeable. Still, in another embodiment, the elongatedmember 162 may include spaced apertures, and each of the apertures maybe covered by a liquid-air separator. The above configurations of theelongated member 162 are provided as examples of certain embodiments.However, it should be noted that other embodiments of the elongatedmember 162 may be alternatively configured as to enable gaseouscommunication while substantially preventing liquid communicationthrough the elongated member 162.

For example, FIG. 4A illustrates a cross-sectional view of the elongatedmember 162 of FIG. 3 taken along line 4-4 in accordance with anillustrative embodiment. The elongated member 162 may consist of a firstportion 402 welded or bonded to a second portion 406. Both the firstportion 402 and the second portion 406 prevents, or substantiallyprevents, the passage of liquid (e.g., exudate) from the liquidcollection chamber 104 into the inner portion, or gas communicationpathway, of the elongated member 162. For instance, in one embodiment,the first portion 402 and the second portion 406 are hydrophobicmembranes. Alternatively, the first portion 402 and the second portion406 may be any material coated with a hydrophobic material to make themsubstantially impermeable to liquid.

In addition, at least one of the first portion 402 and the secondportion 406 allows gaseous communication between the inner portion, orgas communication pathway, of the elongated member 162 and the liquidcollection chamber 104. In one embodiment, at least one of the firstportion 402 and the second portion 406 may be manufactured usingpolytetrafluoroethylene (PTFE), expanded polytetrafluoroethylene(ePTFE), or other fluoropolymer products. For example, in oneembodiment, both the first portion 402 and the second portion 406 may bemade of an ePTFE membrane manufactured by W.L Gore and Associates, Inc.for enabling gaseous communication between the inner portion of theelongated member 162 and the liquid collection chamber 104 whilesubstantially preventing the passage of liquid. The first portion 402and the second portion 406 may be joined by a weld, by an adhesivematerial, and/or by any other suitable means for providing a leak-freeconnection. Alternatively, in some embodiments, the first portion 402and the second portion 406 may be manufactured as a single unit. Forexample, in one embodiment, the first portion 402 and the second portion406 may be a folded sheet that is joined along a single seam.

In another embodiment, as depicted in FIG. 4B, either the first portion402 or the second portion 406 may be made of a material that preventsboth gaseous and liquid communication, while the other of the firstportion 402 or the second portion 406 is made of a material that allowsgaseous communication, but substantially prevents liquid communication.Such a configuration may be less expensive than forming the entireelongated member 162 from gas permeable, liquid impermeable material.

Referring still to FIGS. 3, 4A, and 4B, the elongated member 162 mayinclude a manifold or a biasing member 404 disposed within the conduitbetween the first portion 402 and the second portion 406 to reducecollapse of the elongated member 162 when exposed to reduced pressure.In one embodiment, the biasing member 404 may include a plurality offlow channels to manifold gas flow along the length of the elongatedmember 162. The biasing member 404 may be made of a non-woven material,such as, but not limited to, Libeltex™ TDL2, manufactured by LibeltexGroup. Non woven materials include a range of polyolefin's, polyesters,and acrylics (and blends and laminates) that may be formed by meltblown, air laid, thermo and spun bonded techniques, and include suchsuppliers as Libeltex, Freudenberg, Buckeye, and Fiberweb. In otherembodiments, the biasing member 404 may be made of a woven material; orGranufoam. Woven or textile material includes polyolefin, polyester,acrylics, polyurethanes, and polyamide based fibers, and blends andco-component fibers. Example manufacturers include DuPont, Eastman, andAtex. The biasing member may be formed from a compressible material, oralternatively from a rigid material such as for example by a latticestructure or other framework that is comprised of metal, plastic orother substantially rigid materials.

In addition, in some embodiments, the elongated member 162 may includean odor adsorption material (not depicted) within the conduit, such as,but not limited to, activated charcoal. Alternatively, and/or inaddition to, an odor adsorption material may be placed between theconnection of the substantially planar liquid-air separator 160 and thelid portion 146 of the canister 102.

FIGS. 5A-5D illustrates different configurations of the elongated member162 within the canister 102 of FIG. 1. In the depicted embodiment ofFIG. 5A, the canister 102 is oriented such that gravity is asserted inthe direction as indicted by arrow 500A. FIG. 5A illustrates the basinportion 145 connected to the lid portion 146 of the reduced pressuretreatment unit 140 to form the liquid collection chamber 104. Thesubstantially planar liquid-air separator 160 is connected to therecessed region 158 of the basin portion 145 to receive reduced pressurefrom the reduced pressure source 108 through the canister outlet 156. Inone embodiment, the elongated member 162 is allowed to extend naturallyinto the liquid collection chamber 104 based on the direction ofgravity. However, it should be noted that in some embodiments, theelongated member 162 may be formed, positioned, or manufactured, as tomaintain the depicted shape no matter how the canister 102 is oriented.

As liquid 502 is collected in the liquid collection chamber 104, theportion of the elongated member 162 covered by the liquid 502 becomesblocked and does not allow gaseous communication between the inner spaceof the elongated member 162 and the liquid collection chamber 104.However, the remaining portion of the elongated member 162, or portionsthereof, not covered by the liquid 502 enables gaseous communicationbetween the inner space of the elongated member 162 and the liquidcollection chamber 104 for providing reduced pressure from the reducedpressure source 108. As shown in FIG. 5A, under this orientation of thecanister 102 and configuration of the elongated member 162, the liquidcollection chamber 104 would continue to receive reduced pressure untilthe liquid collection chamber 104 is substantially full of liquid.

FIGS. 5B-5D illustrates other embodiments in which the elongated member162 is positioned, shaped, or manufactured in a particular shape as tooptimally fill the liquid collection chamber 104 in substantially anyorientation of the canister 102 while maintaining reduced pressure inthe liquid collection chamber 104. For instance, FIG. 5B illustrates anembodiment in which the elongated member 162 is positioned, shaped, ormanufactured to extend into the liquid collection chamber 104 in anundulating configuration. As referenced herein, the term undulatingrefers to a wave-like configuration. In FIG. 5B, the canister 102 isoriented such that gravity is asserted in the direction as indicated bythe arrow 500A (as shown in FIG. 5A). Therefore, as liquid 502 entersthe liquid collection chamber 104, the liquid level would start coveringthe bottom portions of the elongated member 162 preventing gaseouscommunication through the covered portions of the elongated member 162.However, the uncovered upper portions of the elongated member 162 wouldcontinue to provide reduced pressure to the liquid collection chamber104. Because the elongated member 162 is configured in such a way thatextends substantially the width of the liquid collection chamber 104,the liquid collection chamber 104 continues to receive reduced pressureuntil the liquid collection chamber 104 is substantially full.

Additionally, because the elongated member 162 undulates tosubstantially cover the area of the liquid collection chamber 104, thecanister 102 may be oriented in substantially any direction, and theliquid collection chamber 104 would still be able to receive reducedpressure until the canister 102 is substantially full. For example,FIGS. 6A-6C illustrates different orientations of the canister 102having the filter configuration illustrated in FIG. 5B. As can be seenin the examples illustrated in FIGS. 6A-6C, no matter how the canister102 is oriented, at least a portion of the elongated member 162 is notcovered by the liquid 502 that allows for gaseous communication.Therefore, using the undulating configuration of the elongated member162 as depicted in FIGS. 6A-6C, the canister 102 is able to maintainreduced pressure in the liquid collection chamber 104 until the liquidcollection chamber 104 is substantially full.

In addition, referring back to the undulating configuration of FIG. 5B,the liquid collection chamber 104 would continue to receive reducedpressure until the canister 102 is substantially full even if onlyportions (e.g., at locations 162A and 162B) of the elongated member 162provide gaseous communication, while the remaining portion of theelongated member 162 is both gas and liquid impermeable.

FIG. 5C illustrates another embodiment in which the elongated member 162is positioned, shaped, or manufactured within the liquid collectionchamber 104 to enable the canister 102 to fill with liquid insubstantially any orientation while maintaining reduced pressure in theliquid collection chamber 104. For instance, in the depicted embodimentof FIG. 5C, the elongated member 162 is configured in an “L” shapeformation that extends substantially the width and length of the liquidcollection chamber 104. Again, the liquid collection chamber 104 wouldcontinue to receive reduced pressure until the canister 102 issubstantially full even if only portions 162C and 162D of the elongatedmember 162 provide gaseous communication, while the remaining portion ofthe elongated member 162 is both gas and liquid impermeable. However, itshould be noted that the elongated member 162 may comprise substantiallyof a liquid-air separator material or may include additionalportions/segments beyond portions 162C and 162D of the elongated member162 that provide gaseous communication, while substantially preventingliquid communication.

FIG. 5D depicts yet another embodiment in which the elongated member 162is positioned, shaped, or manufactured within the liquid collectionchamber 104 to enable the canister 102 to fill with liquid insubstantially any orientation while maintaining reduced pressure in theliquid collection chamber 104. In the depicted embodiment of FIG. 5D,the elongated member 162 is configured in a “U” shape formation thatextends substantially the width and length of the liquid collectionchamber 104. The depicted embodiment of FIG. 5D provides severaladvantages over the prior art. For instance, the “U” shape formation mayprovide more stability to the elongated member 162 by enablingattachment of both ends of the elongated member 162 to the lid portion146 of the reduced pressure treatment unit 140. This may be particularlyadvantageous in embodiments in which the reduced pressure treatment unit140 is mobile unit such as when worn or carried by a patient. Inaddition, in some embodiments, both ends of the elongated member 162 maybe attached to dual canister outlets (not shown) for providing reducedpressure to the canister 102 through multiple outlet ports.

Referring now to FIGS. 7 and 8, another embodiment of an elongatedmember 700 is provided. Beginning with FIG. 7, a generic canister 720having a barb connector 710 for connecting the elongated member 700 tothe canister 720 is illustrated according to an illustrative embodiment.The canister 720 includes a basin portion 722 that forms a liquidcollection chamber 740 when connected to a canister wall 724 of thecanister 720. The basin portion 722 includes an inlet 730 fortransferring reduced pressure to a tissue site (not shown) and forreceiving fluid from the tissue site.

In a preferred embodiment, the barb connector 710 may be formed as anintegral part of the canister wall 724. The barb connector 710 is notlimited to any particular location on the canister wall 724, and may beof varying size, shape, thickness, and depth depending on the particulardesign of the canister 720. In addition, in some embodiments, thecanister wall 724 may include multiple barb connectors for connectingone or more of the elongated member 700 to different locations of thecanister wall 724. In one embodiment, the barb connector 710 forms ahollow gas communication lumen 712 for receiving reduced pressure fromthe reduced pressure source 108. Although FIGS. 7 and 8 illustrate abarb type connector, the elongated member 700 may be coupled to thecanister wall 724 by other means, including using other types ofconnectors and/or fasteners such as a clamp, adhesively bonding orwelding the elongated member 700 to the canister wall 724, or by anyother means for attaching the elongated member 700 to the canister wall724.

The elongated member 700 is completely sealed except at an open end 713.The elongated member 700 connects to the barb connector 710 through theopen end 713 for receiving reduced pressure through the barb connector710. The elongated member 700 forms a conduit that is shaped,positioned, and/or manufactured to extend into the space of the liquidcollection chamber 740 so as to provide optimum coverage for providingreduced pressure to the liquid collection chamber 740.

The elongated member 700 has a conduit wall 702 that forms a gascommunication lumen 704 for transferring reduced pressure received fromthe reduced pressure source to the liquid collection chamber 740. Theconduit wall 702 is substantially liquid impermeable. However, at leasta portion the conduit wall 702 allows gaseous communication between thegas communication lumen 704 and the liquid collection chamber 740. Insome embodiments, substantially the entire portion of the conduit wall702 may allow gaseous communication between the gas communication lumen704 and the liquid collection chamber 740, while substantiallypreventing liquid communication. The conduit wall 702 may be made of thesame or similar material as previously described above with regard tothe elongated member 162. For example, the conduit wall 702 may be madeusing expanded polytetrafluoroethylene (ePTFE) or any other suitablematerial that enables gaseous communication while substantiallypreventing liquid exchange. The conduit wall 702 may be formed as asingle unit or by connecting multiple components/structures togetherusing any suitable connection means such as welding or adhesive. Thelength, width, and thickness of the conduit wall 702 may vary dependingon the particular configurations of the canister 720 so as to providethe optimum use of the liquid collection chamber 740 while maintainingreduced pressure. Additionally, the elongated member 700 may beconfigured within the liquid collection chamber 740 in any configurationas to optimally provide reduced pressure to the liquid collectionchamber 740 such as, but not limited to, the configurations illustratedin FIGS. 5A-5D.

In some embodiments, the gas communication lumen 704 is an empty spacein which reduced pressure can flow. In other embodiments, the gascommunication lumen 704 may include a biasing member 706, such as, butnot limited to, a non-woven material. The biasing member 706 may providestructural support to reduce collapse of the conduit wall when the gascommunication lumen 704 is exposed to reduced pressure. The biasingmember 706 may include a plurality of flow channels to manifold gas flowalong the length of the gas communication lumen 704. In addition, insome embodiments, an odor adsorption material such as activated charcoalmay be added to the biasing member 706 to absorb odor.

FIG. 8 illustrates a cross sectional side view of the elongated member700 connected the barb connector 710 according to an illustrativeembodiment. In one embodiment, the elongated member 700 may be attachedto the barb connector 710 simply by pushing the barb connector 710 intothe open end 713 of the elongated member 700. In some embodiments, theinner portion of the open end 713 may include integrated grooves orridges 701 for enabling the open end 713 of the elongated member 700 tosecurely grip the barb connector 710. The open end 713 may bemanufactured to have any particular size, shape, or thickness dependingon the size and/or shape of the barb connector 710 so as to provide atight leak-free connection. For example, the open end 713 of theelongated member 700 may be circular, oval, triangular, square, or anyother shape that provides an optimal leak-free connection. In someembodiments, an adhesive, weld, clamp, and/or any other material may beapplied to the connection to assist in providing a secure leak-freeconnection between the open end 713 of the elongated member 700 and thebarb connector 710.

Referring to FIG. 9, a canister 902 similar to canister 102 (FIG. 3) orcanister 720 (FIG. 7) includes a canister housing 943 having a basinportion 945 and a lid portion 946. The lid portion 946 may be formed byan exit wall 942 that is substantially planar and is capable of matingwith the basin portion 945 to form a liquid collection chamber. Whilethe basin portion 945 is formed from a basin wall 950 that includescurved contours to create a crescent shape, the basin portion 945 andlid portion 946 may instead form a canister that is cylindrical,cubical, spherical, rectangular cubical, or any other shape. It shouldalso be noted that the canister 902 may not include separate basin andlip portions, but rather may be formed from a substantially unitaryhousing. In such an embodiment, the liquid-collection chamber may bedefined by a single wall. Alternatively, the liquid-collection chambermay be formed by a plurality of walls.

Similar to canister 102 of FIG. 3, canister 902 includes an inlet 998that is configured to be fluidly connected to a conduit, and a canisteroutlet 920 that is fluidly connected to a reduced pressure source. Asubstantially planar liquid-air separator 960 is operatively associatedwith the outlet 920 of the canister 902 to prevent liquid from exitingthe canister 902 through the canister outlet 920. In one embodiment, theoutlet 920 is positioned in the exit wall 942, and the substantiallyplanar liquid-air separator 960 is positioned adjacent to the outlet andsecured to the exit wall 942. The substantially planar liquid-airseparator 960 prevents liquids that that are drawn into the canister 902from exiting the canister 902 through the outlet 920 and contaminatingthe reduced pressure source. In an illustrative embodiment, thesubstantially planar liquid-air separator 960 may be a hydrophobic oroleophobic filter as described previously with reference to liquid-airseparator 160.

In accordance with one embodiment, the canister 902 includes a dividingmember 962 that forms a conduit that allows gaseous communicationbetween the liquid collection chamber and the canister outlet 920 formaintaining reduced pressure in the liquid collection chamber whilesubstantially preventing liquid communication. The dividing member 962includes a wall 964 or membrane that defines a gas-communication pathwayor space similar to that described previously with reference to theelongated member 162 illustrated in FIGS. 4A and 4B. The wall 964 of thedividing member 962 and the dividing member 962 itself may include thesame flexible, or alternatively, rigid characteristics of the elongatedmember 162. At least a portion of the wall 964 is formed from a materialthat allows gaseous communication between the gas-communication space ofthe dividing member 962 and the liquid collection chamber of thecanister 902. The wall 964 or membrane may be formed from a unitarypiece of material, or from two or more pieces of material that arewelded, bonded, or otherwise attached together. The gas-communicationspace may include a biasing material similar to that previouslydescribed with reference to elongated member 162.

The shape of the dividing member 962 is such that it closely matches aninterior profile of the liquid collection chamber of the canister 902,and the dividing member may include a width, W, and a depth, D, that issubstantially equal to a corresponding width and depth of the canisterhousing 943. This particular shaping and sizing of the dividing member962 is such that the dividing member 962 substantially divides theliquid collection chamber of the canister housing 943 into first andsecond chambers or spaces. In the embodiment illustrated in FIG. 9, thedivision of the liquid collection chamber would result in an upperchamber positioned above the dividing member 962 and a lower chamberbelow the dividing member 962.

The dividing member 962 may serve to prevent excessive liquid movementor sloshing within the liquid collection chamber since the liquidcollection chamber is substantially divided. The dividing member 962 mayinclude at least one aperture 980 through the wall of the dividingmember 962 to allow fluid communication between the upper chamber andthe lower chamber of the liquid collection chamber. The placement of theapertures 980 in the dividing member 962 still maintains the sealedintegrity of the gas-communication space within the dividing member 962such that liquid is not able to enter the gas-communication space.

The dividing member 962 is connected to the substantially planarliquid-air separator 960. For example, the dividing member 962 may bewelded to the liquid-air separator 960. In other embodiments, thedividing member 962 may be connected to the substantially planarliquid-air separator 960 using an adhesive material or by any othersuitable means. Alternatively, in some embodiments, the substantiallyplanar liquid-air separator 960 and the dividing member 962 are notseparate components, but rather may be manufactured as a substantiallyunitary liquid-air separator. When coupled, the substantially planarliquid-air separator 960 and the dividing member 962 serve the sameliquid-air-separation purpose of allowing air to move from the canister.In still other embodiments, a substantially planar liquid-air separator960 may not be used, and the dividing member 962 may be directlyconnected to the outlet 920 of the canister 902 such that thegas-communication space is in fluid communication with the outlet of thecanister 902.

Besides the connection of the dividing member 962 to the liquid-airseparator 960 or the outlet of the canister 902, the dividing member962, in any particular embodiment, may be connected to the canister 902at other locations around the perimeter of the dividing member 962. Forexample, in the embodiment illustrated in FIG. 9, the dividing member902 may be connected at each of four corners 986 to one or more walls ofthe canister 902. This supplemental attachment of the dividing member962 to the canister 902 may serve to increase the ability of thedividing member 962 to maintain the divided nature of the liquidcollection chamber. In other embodiments, the dividing member 962 maynot be attached to the canister 902 at locations other than the outletof the canister 902.

While only a few canister shapes have been illustrated and described,use of the filters or elongated elements described herein, and theadvantages that these filters and elongated elements provide, is notlimited to any particular shape of canister. In addition, each of thefilters and elongated elements described herein may be varied in size orshape to better accommodate a canister of a particular size or shape.

While some of the filters presented herein have been described as havinga single interior space or chamber, the number of filter chambers is notlimited. Multiple filter chambers that are either independently orjointly connected to the canister outlet or multiple canister outletsmay be employed, again depending at least partially upon the size andshape of the canister. Similarly, multiple filter elements may be usedto increase the time that the filter maintains gas transmission duringliquid collection activities.

The filters and liquid-collection canisters described herein may be usedas part of a process or method for retrofitting an existing wound fluidcollection canister design or a new wound collection canister design toallow collection of wound fluid in multiple orientations of the woundfluid collection canister. The method includes fluidly connecting anelongated member to an outlet of the wound fluid collection canister. Atleast a portion of the elongated member extends into a liquid collectionarea of the wound fluid collection canister. The method further includesallowing gas exchange between an inner space of the elongated member andthe liquid collection area; and substantially preventing liquid exchangebetween the inner space and the liquid collection area. In someembodiments, the method may further include undulating, shaping,positioning, and/or manufacturing the portion of the conduit extendinginto the liquid collection area of the wound fluid collection canistersuch that gas exchange between the inner portion of the conduit and theliquid collection area is optimally maintained.

It should be apparent from the foregoing that an invention havingsignificant advantages has been provided. While the invention is shownin only a few of its forms, it is not just limited but is susceptible tovarious changes and modifications without departing from the spiritthereof.

While a number of discrete embodiments have been described, aspects ofeach embodiment may not be specific to only that embodiment and it isspecifically contemplated that features of embodiments may be combinedwith features of other embodiments.

We claim:
 1. A canister for collecting liquid from a tissue site towhich reduced pressure treatment is applied, the canister comprising: atleast one canister wall defining a first space configured to collectliquid from the tissue site; a canister outlet configured to allowcommunication between a reduced pressure source and the first space; anelongated member fluidly connected to the canister outlet and extendingaway from the canister outlet into the first space, the elongated memberhaving a membrane defining a second space along at least a portion of alength of the elongated member, at least a portion of the membraneallowing gaseous communication between the first space and the secondspace; and a biasing member surrounded by the membrane and configured toreduce collapse of the elongated member when the second space is exposedto reduced pressure.
 2. The canister of claim 1, further comprising: asubstantially planar, liquid-air separator disposed adjacent thecanister outlet to prevent the liquid from exiting the first spacethrough the canister outlet, the elongated member being connected to thesubstantially planar, liquid-air separator.
 3. The canister of claim 1,wherein the elongated member is connected to the canister outlet using ahose barb attachment.
 4. A canister for collecting liquid from a tissuesite to which reduced pressure treatment is applied, the canistercomprising: a chamber configured to collect liquid from the tissue site;a canister outlet in fluid communication with a reduced pressure source;a flexible member having a gas communication pathway at least partiallydefined by a flexible membrane, the flexible member being positioned inthe chamber such that the gas communication pathway is in fluidcommunication with the canister outlet, at least a portion of theflexible membrane being gas permeable and substantially liquidimpermeable; and a manifold surrounded by the flexible member andconfigured to support the flexible member under reduced pressure.
 5. Thecanister of claim 4, further comprising a substantially planar,liquid-air separator connected to a wall of the canister tosubstantially cover the canister outlet, the flexible member beingconnected to the substantially planar, liquid-air separator.
 6. Thecanister of claim 5, wherein the flexible member and the liquid-airseparator are a single unit.
 7. The canister of claim 5, wherein theflexible member is welded to the liquid-air separator.
 8. The canisterof claim 5, wherein the flexible member is adhesively bonded to theliquid-air separator.
 9. The canister of claim 4, wherein the flexiblemember is connected to the canister outlet using a hose barb attachment.10. The canister of claim 4, wherein the flexible member is connected tothe canister outlet using a clamp.
 11. The canister of claim 1, whereinthe biasing member is configured to manifold gas flow through the secondspace under reduced pressure.
 12. The canister of claim 1, wherein thebiasing member includes a plurality of flow channels.
 13. The canisterof claim 1, wherein the biasing member comprises a compressiblematerial.
 14. The canister of claim 1, wherein the biasing membercomprises a nonwoven material.
 15. The canister of claim 1, wherein thebiasing member comprises a woven material.
 16. The canister of claim 1,wherein the biasing member comprises an open-cell foam.
 17. The canisterof claim 1, wherein the elongated member and the biasing member areflexible within the first space.
 18. The canister of claim 1, whereinthe elongated member is configured to extend into the first space basedon the direction of gravity.
 19. The canister of claim 1, wherein themembrane prevents liquid communication between the first space and thesecond space.
 20. The canister of claim 4, wherein the manifold isconfigured to manifold gas flow through the gas communication pathwayunder reduced pressure.
 21. The canister of claim 4, wherein themanifold includes a plurality of flow channels.
 22. The canister ofclaim 4, wherein the manifold comprises a compressible material.
 23. Thecanister of claim 4, wherein the manifold comprises a nonwoven material.24. The canister of claim 4, wherein the manifold comprises a wovenmaterial.
 25. The canister of claim 4, wherein the manifold comprises anopen-cell foam.
 26. The canister of claim 4, wherein the flexible memberand the manifold are flexible within the chamber.
 27. The canister ofclaim 4, wherein the flexible member is configured to extend into thechamber based on the direction of gravity.
 28. The canister of claim 4,wherein the flexible membrane prevents liquid communication between thechamber and the gas communication pathway.
 29. A canister for collectingliquid from a tissue site to which reduced pressure treatment isapplied, the canister comprising: a chamber configured to collect liquidfrom the tissue site; a canister outlet configured to allowcommunication between a reduced pressure source and the chamber; anelongated member fluidly connected to the canister outlet and extendingaway from the canister outlet into the chamber, the elongated memberhaving a first portion and a second portion, the first portion bonded tothe second portion and forming a gas communication pathway, at least apart of the first portion being gas permeable; and a biasing memberdisposed in the gas communication pathway and configured to reducecollapse of the elongated member when the gas communication pathway isexposed to reduced pressure.
 30. The canister of claim 29, wherein atleast a part of the first portion is liquid impermeable.
 31. Thecanister of claim 29, wherein at least a part of the second portion isgas and liquid impermeable.
 32. The canister of claim 29, wherein thebiasing member is configured to manifold gas flow through the gascommunication pathway under reduced pressure.
 33. The canister of claim29, wherein the biasing member includes a plurality of flow channels.34. The canister of claim 29, wherein the biasing member comprises acompressible material.
 35. The canister of claim 29, wherein the biasingmember comprises a nonwoven material.
 36. The canister of claim 29,wherein the biasing member comprises a woven material.
 37. The canisterof claim 29, wherein the biasing member comprises an open-cell foam. 38.The canister of claim 29, wherein the elongated member and the biasingmember are flexible within the chamber.
 39. The canister of claim 29,wherein the elongated member is configured to extend into the chamberbased on the direction of gravity.
 40. The canister of claim 29, whereinthe first portion and the second portion prevent liquid communicationbetween the chamber and the gas communication pathway.